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Texas Instruments SN74HCS251PWR
- Part No.:
- SN74HCS251PWR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74HCS251PWR.pdf
- Description:
- IC DATA SELECT/MUX 1X8:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:761
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Product details
Overview
SN74HCS251PWR from Texas Instruments is an 8-to-1 CMOS multiplexer with Schmitt-trigger inputs and complementary 3-state outputs, operating from 2 V to 6 V supply. It selects one of eight data inputs (D0–D7) using binary address lines A/B/C, delivers non-inverted (Y) and inverted (W) outputs, and supports bus-oriented systems via OE-controlled high-impedance states. Used in industrial control logic and sensor signal routing where noise immunity and low-power operation are critical.
For engineers reviewing the SN74HCS251PWR datasheet, SN74HCS251PWR pinout, SN74HCS251PWR application, or SN74HCS251PWR equivalent, key selection criteria include its ±7.8-mA output drive at 6 V, –40°C to +125°C temperature range, Schmitt-trigger hysteresis (0.6 V min at 6 V), 3-state enable timing (6 ns disable time), and TSSOP-16 package compatibility with space-constrained PCB layouts.
Technical Context
The SN74HCS251PWR implements full binary decoding for 1-of-8 data selection with strobe-controlled complementary outputs (Y and W). Its Schmitt-trigger inputs provide hysteresis (ΔVT ≥ 0.6 V at 6 V), enabling reliable operation with slow-rising or noisy signals without external conditioning.
It features balanced CMOS 3-state outputs capable of sourcing/sinking ±7.8 mA at 6 V, with propagation delays as low as 6 ns (typical) and disable time of 7 ns (typical) at 6 V. The device operates across the full industrial temperature range (–40°C to +125°C) and draws only 0.1 µA typical supply current at 6 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 2 V to 6 V - supports single-supply operation across legacy 3.3 V and modern low-voltage systems |
| Operating temperature | –40°C to +125°C - qualified for under-hood automotive, industrial PLC, and outdoor embedded applications |
| Output drive | ±7.8 mA at 6 V - sufficient to directly drive multiple CMOS loads or small LEDs without buffering |
| Propagation delay | 6 ns (typ) at 6 V - enables reliable operation up to 29 MHz switching frequency in high-speed digital logic |
| Hysteresis (ΔVT) | 0.6 V min at 6 V - rejects noise spikes ≤ 600 mV peak-to-peak on address or data lines |
| Supply current (ICC) | 0.1 µA typical at 6 V - reduces standby power in battery-backed or energy-harvesting systems |
| Input leakage | ±0.1 µA max at 6 V - ensures stable logic levels even with high-impedance source networks |
Pinout & Package
TSSOP-16 package (5.00 mm × 4.40 mm), thin shrink small-outline package with exposed pad not present; suitable for automated SMT assembly and moderate thermal dissipation requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (D3) | Data input 3 | One of eight parallel data sources selected when CBA = 011; CMOS-level compatible |
| 2 (D2) | Data input 2 | Selected when CBA = 010; Schmitt-trigger input rejects noise on this line |
| 3 (D1) | Data input 1 | Selected when CBA = 001; no external pull-up required due to internal hysteresis |
| 4 (D0) | Data input 0 | Selected when CBA = 000; accepts slow-rising signals down to 100 ns edge rate |
| 5 (Y) | Non-inverted output | Active-high 3-state output; driven only when OE = low; floats when disabled |
| 6 (W) | Inverted output | Complementary to Y; identical timing and drive strength; shares OE control |
| 7 (OE) | Output enable (active low) | Assert low to enable Y/W; high places both outputs in high-impedance state |
| 8 (GND) | Ground reference | Primary return path for all I/O and supply currents; requires solid plane connection |
| 9 (C) | Address select C | MSB of 3-bit binary selector; Schmitt-trigger input tolerates slow clock edges |
| 10 (B) | Address select B | Mid-bit of selector; hysteresis prevents metastability during noisy address transitions |
| 11 (A) | Address select A | LSB of selector; determines D0–D1 pair selection; immune to <600 mV noise |
| 12 (D7) | Data input 7 | Selected when CBA = 111; same electrical specs as D0–D6 |
| 13 (D6) | Data input 6 | Selected when CBA = 110; supports hot-swap-compatible bus isolation when OE controlled |
| 14 (D5) | Data input 5 | Selected when CBA = 101; valid over full temperature range without derating |
| 15 (D4) | Data input 4 | Selected when CBA = 100; input capacitance 5 pF - minimizes loading on driving source |
| 16 (VCC) | Positive supply | 2–6 V rail; requires local 0.1-µF ceramic decoupling capacitor per TI layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Schmitt-trigger inputs | Provides ≥0.6 V hysteresis at 6 V, enabling robust operation with slow or noisy control/data signals without external RC filtering |
| Complementary 3-state outputs | Simultaneous Y (non-inverted) and W (inverted) outputs, both controllable by single OE pin for flexible bus arbitration |
| Low ICC consumption | 0.1 µA typical supply current at 6 V allows use in always-on monitoring circuits with microamp-level budget constraints |
| Wide voltage range | 2–6 V operation supports direct interface with 2.5 V, 3.3 V, and 5 V logic families without level shifters |
| High noise immunity | ±4000-V HBM ESD rating and Schmitt-trigger architecture reduce susceptibility to transient coupling in industrial environments |
Applications
| Industrial Sensor Multiplexing | Automotive Body Control Module |
|---|---|
Use Scenario: Consolidating analog sensor readings (temperature, pressure, humidity) from eight remote locations into a single ADC channel via shared data bus. IC Role / Device Role / Timing Role: Data selector routing time-multiplexed sensor outputs; OE synchronized to ADC sampling window to avoid bus contention. Use Value: Eliminates need for eight separate ADC channels or external analog switches; Schmitt-trigger inputs tolerate long cable runs with induced noise. | Use Scenario: Managing discrete switch inputs (door open/closed, seatbelt buckle, trunk latch) across multiple vehicle zones using a centralized microcontroller. IC Role / Device Role / Timing Role: Digital multiplexer aggregating 8-zone status bits onto a single GPIO port; address lines driven by MCU timer outputs. Use Value: Reduces MCU pin count by 7; ±7.8-mA drive supports direct connection to pull-up networks; 125°C rating suits under-dash mounting. |
| Programmable Logic Interface | Test Equipment Signal Routing |
Use Scenario: Configurable I/O expansion in FPGA-based logic analyzers, where user-selectable signal paths route internal test points to external probes. IC Role / Device Role / Timing Role: Address-programmable data selector feeding configurable logic blocks; Y/W outputs feed parallel capture registers. Use Value: Enables dynamic reconfiguration of signal acquisition paths without FPGA recompilation; 6 ns propagation delay preserves timing integrity. | Use Scenario: Automated test fixture routing stimulus signals from one of eight function generators to a device-under-test (DUT) input. IC Role / Device Role / Timing Role: Precision signal switch controlled by test sequencer; OE used for glitch-free signal handoff between generators. Use Value: Prevents signal contention during generator switching; 3-state outputs isolate inactive sources; TSSOP-16 footprint fits dense test head layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC251PWR | Lacks Schmitt-trigger inputs; standard CMOS inputs require clean, fast-rising signals | Not suitable for noisy or slow-switching environments without external conditioning | Select SN74HCS251PWR when input signal integrity cannot be guaranteed |
| CD74HCT251M96 | TTL-compatible inputs (VIH = 2 V min); higher ICC (2 µA typ); same 3-state outputs and pinout | Designed for mixed 5 V TTL/CMOS systems; less tolerant of sub-2 V logic swings | Choose CD74HCT251M96 only when interfacing with legacy 5 V TTL controllers |
Compared with SN74HC251PWR and CD74HCT251M96, the SN74HCS251PWR uniquely combines Schmitt-trigger noise immunity, ultra-low ICC, and wide 2–6 V operation-making it optimal for modern low-power, mixed-voltage, and electrically harsh designs where signal conditioning is impractical.
Availability
SN74HCS251PWR is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and test equipment requiring stable component supply, extended temperature support, and noise-immune signal routing.
Supply support for SN74HCS251PWR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and consumer markets.
The SN74HCS251PWR belongs to TI's HCS logic family, engineered for high-noise environments and low-power operation in space-constrained embedded systems requiring reliable digital signal selection without external signal conditioning.
FAQ
What is the maximum capacitive load the SN74HCS251PWR can drive while meeting all datasheet specifications?
The SN74HCS251PWR is characterized for CL = 50 pF in switching characteristics testing. While larger loads may be driven, performance parameters-including propagation delay, transition time, and output voltage levels-may degrade beyond this value. For guaranteed compliance with datasheet limits, keep total output capacitance ≤50 pF, including PCB trace, probe, and load capacitance. The SN74HCS251PWR's 5 pF input capacitance helps minimize loading on upstream drivers.
Does the SN74HCS251PWR support hot-swap or live-insertion applications?
The SN74HCS251PWR does not include built-in hot-swap protection features such as slew-rate limiting or back-drive prevention. However, its 3-state outputs and Schmitt-trigger inputs allow safe implementation in hot-swap scenarios when OE is asserted high before insertion and held until power stabilization. TI recommends using series resistors and local decoupling per layout guidelines. The SN74HCS251PWR's ±4000-V HBM ESD rating enhances robustness during handling, but system-level protection remains the designer's responsibility.
Can unused address inputs (A, B, C) on the SN74HCS251PWR be left floating?
No. Unused address inputs on the SN74HCS251PWR must be terminated to a defined logic level-either VCC or GND-using direct connection or a pull-up/down resistor (e.g., 10 kΩ). Floating inputs risk undefined selection behavior, increased ICC, and potential oscillation due to noise coupling. This requirement applies regardless of Schmitt-trigger hysteresis, as indeterminate voltage levels between VT− and VT+ cause unpredictable output states. The SN74HCS251PWR's datasheet explicitly mandates termination for all unused inputs.
How does the SN74HCS251PWR behave when OE is high and address lines change?
When OE is high, both Y and W outputs enter high-impedance (Z) state regardless of address (A/B/C) or data (D0–D7) input states. Changing address lines under OE = high has no effect on output voltage or current-outputs remain in Z state with leakage current ≤±0.5 µA. This behavior enables safe bus sharing, as the SN74HCS251PWR electrically isolates its outputs from the bus while internal logic continues toggling. The SN74HCS251PWR's disable time (tdis = 7 ns typ at 6 V) defines the delay from OE rising to full high-Z establishment.
Is the SN74HCS251PWR RoHS-compliant and lead-free?
Yes. The SN74HCS251PWR is RoHS-compliant and lead-free, with NIPDAU (nickel/palladium/gold) lead finish. Per TI's packaging addendum, it carries "Yes" in the RoHS column and meets JEDEC J-STD-020 moisture sensitivity level (MSL) 1 rating (unlimited floor life at ≤30°C/60% RH). The SN74HCS251PWR's TSSOP-16 package is compatible with standard lead-free reflow profiles up to 260°C peak.
SN74HCS251PWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCS
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Data Selector/Multiplexer
- Circuit:
- 1 x 8:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
SN74HCS251PWR FAQ
1.How can I place an order for SN74HCS251PWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCS251PWR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74HCS251PWR reliable?
The price and inventory of SN74HCS251PWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCS251PWR is usually 5 days.
3.What payment methods are accepted for SN74HCS251PWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCS251PWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCS251PWR?
SN74HCS251PWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCS251PWR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74HCS251PWR?
For technical support, including SN74HCS251PWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCS251PWR requirements.
6.How does Aetrix verify that SN74HCS251PWR is sourced from the original manufacturer or authorized distributors?
All SN74HCS251PWR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74HCS251PWR meets industry standards.
7.What is the process for return or replacement of SN74HCS251PWR?
All SN74HCS251PWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCS251PWR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74HCS251PWR part is unused and in its original packaging.
Return procedure for SN74HCS251PWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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